1. Field of the Invention
The present invention relates to an output selection control system for selectively operating a plurality of loads or selectively bringing a load having a plurality of operating conditions into its operating conditions in accordance with the selected closing sequence of a switch. More particularly, the present invention relates to a control system for controlling the operation of a vehicle wiper assembly capable of performing a low-speed wiper operation, a high-speed wiper operation and an intermittent wiper operation.
2. Description of the Prior Art
In the past, to selectively operate a plurality of loads has required the provision of as many switches (or contacts) as there are the loads, while it has been the practice to selectively operate a load having a plurality of operating conditions through a variable resistance element so as to change the output modes of a single switch.
Particularly, two types of vehicle wiper assembly have heretofore been used widely, namely, one in which a manual wiper switch is provided with three operating positions for operating the wiper, i.e., the stopping, low-speed wiper operation and high-speed wiper operation positions and the other in which the manual wiper switch further includes a contact for the intermittent wiper operation in addition to the three operating positions.
To modify the known type of vehicle wiper assembly including a three-operating-position wiper switch so that the wiper assembly can additionally perform the intermittent wiping function, it is necessary to provide not only a control circuit for the intermittent wiper operation but also a separate switch for the intermittent wiper operation in addition to the above-mentioned conventional three-position wiper switch. Otherwise, it is necessary to replace the wiper switch having three operating positions with a wiper switch having four operating positions, i.e., a switch position for the intermittent wiper operation and the above-mentioned three operating positions.
On the other hand, to modify the conventional wiper assembly having a four-operating-position wiper switch originally provided with the function of intermittent wiper operation so that the wiper assembly can perform two intermittent wiper operating functions having two different operating time constants for the intermittent wiper operation, it is necessary to replace the wiper switch having four operating positions with a wiper switch having five operating positions, i.e., the above-mentioned four operating positions and an additional operating position.
However, the provision of a separate switch or the replacement of one switch with another is contrary to the needs of the recent years, that is, the saving of material and the effective utilization of the driver's compartment, in particular the space on the instrument panel.
In other words, the provision of a separate (independent) switch for providing the wiper assembly with an additional function of intermittent wiper operation or an additional intermittent wiper operation function for intermittently operating the wiper with different operating time constants has the disadvantage of requiring an additional space and hence giving rise to an increased manufacturing cost, whereas the replacement of a wiper switch having three operating positions with one having four operating positions or replacing a wiper switch having four operating positions with one having five operating positions gives rise to waste of material and complication of assembling process.